Ischemic stroke in oral anticoagulated patients with atrial fibrillation

Background Ischemic strokes in orally anticoagulated patients pose challenges for acute management and secondary prevention but the characteristics of these strokes are poorly understood. We examined the clinical and imaging features, the presumed underlying etiology and the subsequent antithrombotic management. Methods We analyzed a consecutive series of patients enrolled into the EIDASAF study, a single center, observational study of ischemic stroke patients with a diagnosis atrial fibrillation (AF) prior to the index event who had been admitted to the Hyperacute Stroke Unit of Imperial College London between 2010 and 2017. We compared patients with oral anticoagulation therapy prior admission (OAC(prior)) with those without anticoagulation (OAC(naive)). Brain imaging was analyzed centrally. Results 763 patients were included in the analysis. 481 (63%) were OAC(naive) while 282 (37%) were OAC(prior). Patients with OAC(prior) were younger, more often had a previous history of stroke or transient ischemic attack (TIA), and more often suffered from hypertension and diabetes. In OAC(naive,) patients, large and deep middle cerebral artery infarcts occurred more often than in OAC(prior) patients. The groups differed significantly in the distribution of competing etiologies underlying their stroke. At discharge, OAC(prior) more frequently were (re)-anticoagulated compared to OAC(naive) patients. Within the OAC(prior) group, patients with recurrent strokes did not differ from those with a first stroke regarding clinical characteristics and pattern of cerebral infarction but they were less frequently anticoagulated. Conclusions Ischemic strokes on OAC represent a significant proportion of AF-related strokes. There is an unmet need to better understand the causes underlying these strokes and to optimize the medical management.